General Operation

Operation Basics

The operation of a windmill is a relatively simple concept that uses the wind in order to operate the pumping cylinder underground and bring water to the surface. By converting the rotary motion of the windmill wheel into a steady up and down pumping stroke, the piston-pump underneath the windmill in the water table underground will push the water upwards towards the surface. The modern water-pumping windmill has gone through very little evolution in the past century and serves as a testament to its perfect design.

Video Courtesy of The American Wind Power Center

Capturing the Energy of the Wind

When the windmill is turned on, the mill orients into the wind in order to capture the renewable energy in the wind and turn the blades on the windmill wheel. As the wheel spins, it turns the mechanical gears in the motor which then lifts and lowers the pumping rod or “sucker rod” at the base of the motor. This up and down pumping stroke action pushes the water up through the drop pipe and into a stock tank or other storage tank.

OPERATION BASICS

The water table located above the underlying aquifer is where water-bearing permeable rock has allowed groundwater to collect in sufficient levels to be extracted. The depth of this water table differs from region to region and correlates directly with how deep a water well needs to be drilled. It is here, in the depths of the water table, where the windmill operates the pump. The pumping action forces the water through perforations in the drop pipe and into the windmill cylinder. The water will only be allowed to flow upwards in the well due to the actions of the valves in the pumping cylinder.

Inside the cylinder are two valves. The valve directly attached to the sucker rod at the top of the cylinder is the “plunger”. The valve attached to the bottom of the cylinder is the “check” valve. Each valve will operate directly opposite of each other.

As the sucker rod moves up and down, it lifts and lowers the “plunger” directly attached to the rod. As this plunger rises up on the “upstroke”, the ball inside will be seated or “closed”, sealing off the water that has been trapped above it, allowing it to be lifted up the pipe with each consecutive stroke. When the plunger is lowered on the “downstroke”, the ball in the plunger will lift up or “open” allowing the water below the ball to flow upwards past the valve. Remember: When the plunger valve rises, the ball inside will be lowered or “closed”, and when the plunger lowers, the ball inside will be lifted or “open”.

The lower valve, or “check valve” is where the water will be initially drawn into the well. As the sucker rod pulls the plunger upwards, the ball inside the check valve will rise, allowing more water to flow into the cylinder. When the plunger is lowered back down on the down stroke of the pump, the ball inside the check valve will seat, or “close”, trapping the water above it, and allowing the plunger to pull this water upwards past the ball inside the plunger. Remember: When the plunger valve rises, the ball in the check valve will be lifted or “open”, and when the plunger lowers, the ball in the check will be lowered or “closed”.

The column of water that has been built up past the plunger will be pushed upwards until it flows out of the top of well into a storage tank. This cycle is repeated until the windmill is turned off or the wind stops blowing. When the pumping stops, both valves will close and trap the column of water above the plunger in the pipe. When the mill begins to turn again, the pumping action will pick up where it left off and continue to push the water upwards out of the well.